Introduction of muffle furnace and precautions for use

Classification of muffle furnaces Muffle furnaces are divided into domestic muffle furnaces and imported muffle furnaces according to nationality
.

According to the heating elements, there are: electric furnace wire muffle furnace, silicon carbon rod muffle furnace, silicon molybdenum rod muffle furnace; according to the rated temperature, it is generally divided into: 900 degree series muffle furnace, 1000 degree muffle furnace, 1200 degree muffle furnace Muffle furnace, 1300 degree muffle furnace, 1600 degree muffle furnace, 1700 degree muffle furnace
.

According to the controller, there are the following types: pointer table, ordinary digital display table, PID adjustment control table, program control table; according to the insulation material, there are two kinds: ordinary refractory brick and ceramic fiber
.

Therefore, users must write clearly in the contract when purchasing products, so as to avoid suppliers playing tricks
.

The structure and parameters of the muffle furnace The muffle furnace is divided into two parts: the furnace body and the intelligent controller.
Some muffle furnaces are integrated with the furnace body and the controller, while others are separated
.

The muffle furnace is mainly heated by electric furnace wire, which is divided into two-sided heating, three-sided heating, etc.
; the ordinary brick structure muffle furnace has a slower heating rate, while the ceramic fiber structure is light in weight, and has a fast heating rate, which saves energy.
At the same time, the service life has also been improved
.

There is also the controller.
The slightly worse is the pointer type, which is read manually, and the better is intelligent control.
The temperature control is more accurate than the pointer type temperature control, which reduces the error of visual reading and manual operation; Another is the most basic parameters of an excellent muffle furnace with a temperature sensor is the volume and the maximum temperature range: The volume of commonly used muffle furnaces is 4, 6, 10, 22, 30, 45L, and the common maximum temperature of domestic muffle furnaces For 1000 ℃ and 1200 ℃ two
.

Scope of application The muffle furnace is a periodic operation type, which is used for elemental analysis and determination in laboratories, industrial and mining enterprises, and scientific research units and heating for general small steel parts such as quenching, annealing, tempering and other heat treatments.
The high-temperature muffle furnace can also be used for metal and ceramic sintering , dissolution, analysis and other high temperature heating
.

 　　(1) Thermal processing, cement, building materials industries, thermal processing or processing of small workpieces
.

 　　(2) Pharmaceutical industry: used for drug testing, pretreatment of medical samples,
etc.

 　　(3) Analytical chemical industry: as sample processing in water quality analysis, environmental analysis and other fields
.

It can also be used for petroleum and its analysis
.

 　　(4) Coal quality analysis: used to determine moisture, ash content, volatile content, ash melting point analysis, ash component analysis, and elemental analysis
.

It can also be used as a general-purpose ashing furnace
.

 　　Safety operation rules and cleaning of muffle furnace 1.
Safety operation rules of muffle furnace: (1) Before starting the furnace, check the tightness of the gas pipeline valve and the pressure on the gas pipeline should not be lower than the specified value
.

 　　(2) Test the working conditions of the push rod mechanism, the pull rod mechanism and the lifting mechanism in an empty furnace
.

 　　(3) Loosen the compression spring to the specified size range
.

 　　(4) Adjust the water level of the water seal, open the valve of the water seal to discharge the combustion pipe, and close the valve of the water seal
.

 　　(5) Close the furnace door at the feeding end, open the furnace door at the discharging end to observe, and close the furnace door when the direction of the mist-like flow is normal when the kerosene is sprayed out
.

 　　(6) Light the burner of the feed chamber
.

 　　(7) Exhaust gas should be discharged through the valve without water seal
.

 　　(8) In intermittent production, the furnace tank is first carburized
.

 　　(9) When the parts are placed, the distance between the parts and the parts is not less than 5 mm; the edge of the parts does not exceed the length of the bottom plate and the specified height
.

 　　(10) The feeding door and the discharging door should be opened and closed quickly, but the speed of the push-pull rod should be stable
.

 　　(11) The position of the parts in the pre-cooling chamber should be directly under the thermocouple
.

 　　(12) Only 24 chassis are allowed to be filled in the furnace.
To continue feeding, you must first pull and then push
.

 　　(13) When the furnace is stopped, the temperature of each furnace area should be lowered to the same temperature, and then the natural cooling should be started
.

 　　2.
Cleaning of muffle furnace equipment: (1) The furnace tank is cleaned once a week during continuous production.
The cleaning of the furnace tank in intermittent production should be carried out immediately after the furnace is stopped.
(2) The furnace tank cleaning temperature is 850 ~ 870 ℃ (3) When blowing in from the feed end of the furnace with a compressed air nozzle, the valve should not be opened too much, and it must be moved back and forth, left and right when blowing, to prevent local overheating; (4) The gas burner is carburizing Wash once with kerosene before
.

 　　(5) After the chassis or fixture is quenched, it should be returned to the pre-cooling room to remove oil stains
.

 　　(6) If the exhaust gas pipe is found to be blocked (the pressure in the furnace suddenly increases), it should be cleaned up immediately
.

First open the waste gas valve that does not pass through the water seal, and then close the waste gas pipe valve that passes through the water seal
.

After cleaning, first open the valve of the waste gas pipe with water seal, and then close the waste gas valve without water seal
.

 　　Maintenance and precautions of the muffle furnace 1.
When the muffle furnace is used for the first time or is used again after long-term deactivation, it must be dried
.

The oven time should be four hours at room temperature of 200°C
.

200℃ to 600℃ for four hours
.

When using, the maximum furnace temperature should not exceed the rated temperature, so as not to burn the electric heating element
.

It is forbidden to pour various liquids and easily soluble metals into the furnace.
The muffle furnace is best to work below the maximum temperature of 50 °C, and the furnace wire has a longer life
.

 　　2.
The muffle furnace and controller must work in a place where the relative humidity does not exceed 85%, and there is no conductive dust, explosive gas or corrosive gas
.

When the metal material with grease and the like needs to be heated, a large amount of volatile gas will affect and corrode the surface of the heating element, destroying it and shortening its life
.

Therefore, when heating, it should be prevented in time and sealed containers or appropriate openings should be excluded
.

 　　3.
The muffle furnace controller should be limited to use within the ambient temperature range of 0-40 °C
.

 　　4.
According to the technical requirements, regularly check whether the wiring of the electric furnace and the controller is in good condition, whether the pointer of the indicator is stuck and stagnant when moving, and use the potentiometer to calibrate the instrument due to magnetic steel, demagnetization, wire expansion and shrapnel.
Error increase caused by fatigue, balance damage,
etc.

 　　5.
Do not pull out the thermocouple suddenly at high temperature to prevent the jacket from bursting
.

 　　6.
Always keep the furnace clean and remove oxides and the like in the furnace in time
.